Hi!
You can hide that switch with this option: https://i.imgur.com/HZfUXCd.png
As for the filters, the answer is it depends. By default an unchecked checkbox is considered an exclusion + items which have no relation to that taxonomy are also displayed. In most cases this default behavior is expected.
In your case I suspect you want to show items which strictly match any of the categories and also hide anything else. In that case this is the configuration you are looking for: https://i.imgur.com/fR60hXS.png
